From: Jeff L Jones (firstname.lastname@example.org)
Date: Thu Mar 20 2008 - 21:05:44 MDT
On Thu, Mar 20, 2008 at 7:54 PM, Jeff L Jones <email@example.com> wrote:
> In our universe however, which contains dark energy, the situation is
> different. There *is* an event horizon about 16-billion light years
> away. (Note that it's a bit further away than 13-billion lightyears,
> the Hubble horizon, but not as far as the current "radius of the
> visible universe" which is 45-billion lightyears... the distance to
> the furthest objects we can currently see). This event horizon is
> created by the fact that the expansion is accelerating, which traps
> light in a region of size 16-billion lightyears (and this region is
> currently shrinking). So in a sense, we *are* in a black hole.
> Although it's again usually not said that way.
Actually, I think the reason why it's not called a black hole is
because we are *outside* the event horizon (from our perspective at
least). Although the event horizon (sometimes called the deSitter
horizon) does radiate Hawking radiation just like any black hole
would. So it has a temperature and all of the usual properties
associated with black holes. But it's due to the dark energy, not due
to the matter density in our region.
This archive was generated by hypermail 2.1.5 : Mon Jun 17 2013 - 04:01:05 MDT